1. Field of the Invention
The present invention relates to an image forming apparatus including a developing device that is detachably attached to a main body of the image forming apparatus. More particularly, the present invention relates to an image forming apparatus including a plurality of driving units which drive the developing device independently of each other.
2. Description of the Related Art
Recently, there have been increasing demands for color copy machines in offices, and tandem-drum-type copy machines including a plurality of photosensitive drums, which are advantageous in view of printing speed, have become popular. Various types of inner structures are adopted in tandem-drum-type copy machines. For example, a structure in which four photosensitive drums are arranged in a horizontal direction is relatively commonly used.
Japanese Patent Laid-Open No. 2001-222207 discusses an apparatus including an open-close unit that can be opened and closed. The open-close unit is opened and closed to allow process cartridges to be attached to or detached from the apparatus.
A developing section generally includes a developing-agent holding member for developing a latent image and a conveying member for mixing and conveying a developing agent. The developing-agent holding member and the conveying member may be driven independently of each other. Accordingly, a plurality of motors may be provided to drive the developing-agent holding member and the conveying member under optimum driving conditions.
In the case where there is only one driving motor for driving the developing device, the driving motor is disposed behind the developing device in the direction in which the developing device is detached from the apparatus. Therefore, the developing device does not interfere with the driving motor when the developing device is attached to or detached from the main body of the apparatus.
In the case where a plurality of driving motors are provided to drive the developing device, it is difficult to place all of the driving motors behind the developing device because the space is limited. Therefore, one or more of the driving motors may be provided in front of the developing device. However, in such a case, the driving motors placed in front of the developing device must be removed to take out the developing device from the main body of the apparatus, and the ease of maintenance is reduced.